JPH11212341A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve soft pressure-contact development and to form an image which is high in resolution and less in density fluctuation. SOLUTION: A supply member 26 is disposed in pressure contact with a toner carrier 32 having hardness greater than that of the supply member 26 but not greater than specific hardness, and is rotated and driven in the same direction as the toner carrier 32, thereby stripping and supplying toner 7. By pressing a plate-spring-like regulation member 35 against the toner carrier 32, the toner 7 is electrified to a specific polarity and also is formed into about one to two thin layers. This makes it possible to provide the developing device which is capable of soft pressure-contact development, the formation of an image with high resolution and less density-change, and is small and inexpensive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus used for electrophotography and the like, and more particularly, to a developing apparatus for developing an electrostatic latent image formed on a latent image carrier with toner. More specifically, the present invention relates to a developing device for forming a uniform thin toner layer on a toner carrier and performing development.

[0002]

2. Description of the Related Art A conventional developing device is disclosed in JP-A-47-130.
No. 88, JP-A-47-13089, which transports and develops toner by a toner carrier having a foamed member as a backing and a flexible conductive layer provided on the surface of the foamed member. there were.

Another developing device is disclosed in
As disclosed in Japanese Patent Application Laid-Open No. 5-77764, a developing device that transports and develops toner by using a toner carrier using a foam material has been proposed.

Further, as another developing device, as disclosed in Japanese Patent Application Laid-Open No. 52-125340, a toner carrier having a rubber surface is used to convey and develop the toner, and the toner on the toner carrier after the development is developed. There has been proposed a developing device having an adjusting member for removing the unevenness of the toner layer.

Further, as another developing device, as disclosed in JP-A-3-155575, in a supply member having a surface layer formed of a polyurethane foam, a developing device having a cell diameter of the foam of 30 to 200 μm is used. A device has been proposed.

Further, as another developing device, as disclosed in Japanese Patent Application Laid-Open No. 4-109266, an uneven portion is provided on the surface of a supply member, and a rotation speed V ₁ [mm / sec] of a toner carrier is provided. , The rotation speed of the supply member V ₂ [mm
/ Sec], the contact width a [mm] between the toner carrier and the supply member in the rotation direction, and the number N of protrusions of the uneven portion per unit length in the rotation direction of the supply member N [pieces / mm]. In between, V
₂ ≧ V _1/4 and 6 ≦ N * a * (V 1 + V 2) / V 1 ≦ 4
A developing device having a relationship of 0 has been proposed.

[0007]

However, in the prior art as disclosed in the above-mentioned JP-A-47-13088 and JP-A-47-13089, the toner carrier is mounted on the toner carrier by using its own weight. Since the toner is supplied, uneven density and ghost due to the development history (irregularities of the toner layer due to the pattern printed immediately before) may occur,
When a white pattern that is not printed continues, the amount of toner transported on the toner carrier gradually increases, causing uneven density or toner adhesion (ground fog) to non-image portions, or the variation in the amount of toner transported. Fluctuations in rotational torque and rotational unevenness of the body occurred, causing print jitter. Therefore, in such a developing device, only an image having a large density unevenness, a low resolution and a large amount of jitter was obtained, and the reliability was low.

In the prior art disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Sho 55-77764, a bias voltage is applied between a toner carrier using a foamed material and a supply member to form a toner layer. (Pre-development) was effective in stably forming the toner layer on the toner carrier, but not only required an extra bias power supply but also increased the size of the developing device.

Further, the aforementioned Japanese Patent Laid-Open No. 52-125340
In the related art as disclosed in Japanese Patent Application Laid-Open No. H11-209, the density unevenness and ghost caused by the history of development can be reduced by the adjusting member, but when a white pattern that is not printed continues, the toner transport amount gradually increases. Uneven density and background fog were generated, and the printing quality was reduced.

Further, in the prior art as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 3-155575, hardening of a supply member due to clogging of a foam material, which is likely to occur when using a small particle size toner, due to toner clogging. Although it was effective in suppressing the so-called filming phenomenon, the consumption history remains in the toner layer on the surface of the toner carrier, and the previous consumption history remains afterimage corresponding to the subsequent rotation cycle of the toner carrier. (Ghost).

Further, in the prior art disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 4-109266, when a small particle size toner is used, a relatively good image can be obtained at a stage where the number of developments is small. Developing a solid image of high density continuously in the developing direction after repeating a number of times causes the disadvantage that the density at the rear end of the solid image decreases, and the consumption history remains in the toner layer on the surface of the toner carrier, and the subsequent toner carrying There was a disadvantage that the previous consumption history appeared as an afterimage corresponding to the body rotation cycle.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a developing apparatus capable of stably performing soft pressure welding development using a flexible elastic body. It is in. Still another object is to provide a developing device with high resolution and little density fluctuation. It is still another object of the present invention to provide a developing device which keeps a constant amount of toner transported on a toner carrier irrespective of the remaining amount of toner and a printing history, and has less density unevenness and less printing jitter. It is still another object of the present invention to provide a developing device capable of obtaining a high-quality image with a low density of a solid image and little occurrence of an afterimage over a long period of time.

[0013]

According to the present invention, in order to visualize a latent image formed on a latent image carrier, the latent image carrier is disposed so as to face the latent image carrier, and at least has a hardness higher than the hardness of the supply member. A toner carrier having a large size, the supply member moving relative to the toner carrier so as to supply the toner to the toner carrier, and being pressed against the toner carrier; and providing a thin layer of the toner supplied on the toner carrier. In a developing device having a regulating member that slides on the toner carrier, a contact position between the toner carrier and the supply member is disposed below a rotation center of the toner carrier, and the toner carrier and The contact position with the regulating member is arranged above the rotation center of the toner carrier, and from the contact position between the toner carrier and the supply member to the contact position between the toner carrier and the regulating member. The tona The central angle with respect to the rotational center of the carrier, characterized in that a 45 ° or more 90 ° or less.

[0014]

According to the above construction of the present invention, the supply member separates or uniformizes the toner layer on the toner carrier and supplies the toner to the toner carrier. They are arranged to face each other so as to have a contact pressure, and are rotationally driven so that the rotational direction of the toner carrier is the same as that of the toner carrier (moving in the opposite direction at the facing portion between the supply member and the toner carrier).
By performing such an arrangement and driving with respect to the supply member, the supply member mechanically peels off the non-uniform toner layer remaining on the toner carrier after the development while the charge is removed, and is sent from the toner storage container. The toner can be supplied to the toner carrier after being uniformly friction-charged again with the new toner that comes.

The toner carrier is pressed by a pressure member by a regulating member, and the toner is frictionally charged to a predetermined polarity at a deformed portion of the toner carrier by the pressing force of the regulation member, and the toner is thinned to about one or two layers. The toner is transported to the latent image carrier while the toner in a thin layer state is directly held by rotating the toner carrier with the layer formation. Further, the toner carrier is pressed against the latent image carrier at a predetermined pressure, and the potential contrast of the latent image carrier and the potential contrast between the latent image carrier and the toner carrier at or near the pressure contact portion (or A developing electric field is formed by the developing bias applying means applied between the latent image carrier and the regulating member, and the latent image is visualized by the toner charged in accordance with the developing electric field.

[0016]

FIG. 1 is a schematic view of a developing device according to an embodiment of the present invention. A latent image carrier 1 has an organic or inorganic photoconductive material on a conductive support 2. The photosensitive layer 3 is formed. After charging the photosensitive layer 3 using a charger 4 such as a charging roller,
The light emitted from a light source 5 such as a laser or an LED is formed into an imaging optical system 6.
The photosensitive layer 3 is selectively irradiated with light in accordance with an image through the process to obtain a potential contrast to form a desired electrostatic latent image pattern.

On the other hand, the developing device 31 transports and develops the toner 7, and a blade-like member made of non-magnetic or magnetic metal or resin is applied to the toner carrier 32 which transports the toner 7. Pressing by the regulating member 35, the regulating member 35 is elastically deformed, the toner 7 is charged to a predetermined polarity at the contact portion of the toner carrier 32, and the toner layer is
The toner 7 is directly thinned to about two layers, the toner 7 is directly held on the toner carrier 32, and the toner 7 is conveyed to the latent image carrier 1 in a state where the toner carrier 32 is rotated and thinned.

The supply member 26 separates or uniformizes the toner layer on the toner carrier 32 and supplies the toner 7 to the toner carrier 32, and has a predetermined contact pressure with the toner carrier 32. And is rotated so that the rotation direction is the same as that of the toner carrier 32 (the contact portion between the supply member 26 and the toner carrier 32 moves in the opposite direction). By performing such an arrangement and driving with respect to the supply member 26, the supply member 26 mechanically peels off the non-uniform layer of the toner 7 remaining on the toner carrier 32 after the development, while removing the charge. The toner can be supplied to the toner carrier 32 after being uniformly friction-charged again with new toner sent from the printer.

The toner carrier 32 is pressed against the latent image carrier 1 at a predetermined pressure, and at or near this pressure contact portion, the potential contrast of the latent image carrier 1 and the potential difference between the latent image carrier 1 and the toner carrier. 32 (or the latent image carrier 1
A developing electric field is formed by the developing bias applying means 8 applied between the developing member and the regulating member 35), and the latent image is visualized by the toner 7 charged in accordance with the developing electric field. Thus, the electrostatic latent image pattern on the latent image carrier 1 is visualized by the charged toner 7. Further, an image formed by the toner 7 is transferred onto the recording paper 10 using a transfer device 9 such as a transfer roller, and the toner 7 is fixed on the recording paper 10 using heat or pressure to form a desired image on the recording paper 10. can do.

The toner carrier 32 is formed by forming a solid member 34 made of a continuous elastic material such as rubber or elastomer having a thickness of about several mm on the outer periphery of a shaft 33 made of metal or resin. It is formed to have a thickness of about several micrometers according to JIS (10-point average surface roughness). By forming the toner carrier 32 from a solid member having a hardness of 60 degrees or less (JIS A) or less, the developing nip length can be 1 mm or more even at a low developing pressure of 10 gf / mm or less, and a stable nip with the latent image carrier can be obtained. While maintaining the pressure contact state, the frictional load between the supply member and the regulating member is reduced, the rotation unevenness of the toner carrier is reduced, and an image with less print jitter can be formed.

Although the urethane rubber is used for the solid member 34 in this embodiment, similarly, rubber such as natural rubber, silicon rubber, butadiene rubber, chloroprene rubber, neoprene rubber, EPDM, NBR, styrene resin, It is also possible to use an elastomer containing a vinyl chloride resin, a polyurethane resin, a polyethylene resin, a methacrylic resin, or the like.

Further, a flexible layer 2 is formed on the surface of the solid member.
By forming No. 5, the frictional load can be reduced, and the charging and conveyance of the toner can be stabilized. Further, by subjecting the surface of the solid member to a hardening treatment using a heat treatment or a chemical treatment, it is possible to reduce a frictional load and to form a highly durable toner carrier.

It is desirable that at least the surface of the toner carrier 32 is conductive in order to realize high-resolution printing by the developing electrode effect. The developing nip formed by the pressure contact portion between the toner carrier and the latent image carrier is about 1 mm, and in order to realize a printing speed up to about 20 PPM, a developing current can be supplied in a short developing time. A sufficiently small time constant is required, and as a toner carrier, 1
It is desirable to have a resistance of ⁰⁹ Ω or less.

The regulating member 35 can be made of a thin plate spring made of a metal such as stainless steel or phosphor bronze and having a thickness of about several hundred μm, or a thin resin such as rubber or elastomer. Since the regulating member 35 is thin and easily deformed, the regulating member 35 is sandwiched and fixed by a fixing plate 36 having a relatively large thickness.
2 is pressed. By pressing the vicinity of the leading end of the regulating member 35 against the toner carrier 32, a thin toner layer can be formed at a low pressure of about several g / mm. Suppress the occurrence of filming. Further, if a bent portion is provided or a member for correcting the flow is added so as to correct the toner flow near the leading end contact portion of the restricting member 35, the restricting member 35 may be provided.
Accordingly, the toner separated from the toner carrier 32 can be returned to the supply member 26 stably.

The material used for the regulating member 35 is a metal such as steel, stainless steel, brass or aluminum, a resin such as silicon or urethane, or a conductive material obtained by dispersing a conductive fine powder such as carbon black in these resins. Resin. Further, a charge controlling agent such as a metal complex salt dye or a quaternary ammonium salt is applied to the surface of the regulating member 35 so that the seven layers of the toner formed on the toner carrier 32 are insufficiently charged or excessively charged. Etc. can be reduced.

The supply member 26 is formed by forming a foam member 28 having a predetermined cell density (foam cell diameter is several tens to 1,000 μm) on the outer periphery of a shaft 27 formed of metal or resin. The foam member 28 is formed by internally adding a conductive pigment such as carbon black or an ion conductive agent such as a metal complex salt to the foam member, or impregnating the foam member with a binder in which the conductive material is dispersed. ^It is a conductive foam having a specific resistance of ⁸ Ωcm or less.

Further, in this embodiment, the foamed member 28 is made of polyurethane foam, but similarly, polystyrene, styrene-acrylonitrile copolymer, ABS,
Polyethylene, polypropylene, polyvinyl chloride, polyvinyl alcohol, acetylcellulose, polyamide,
Foams such as phenolic resin, epoxy resin, urea resin, acrylic resin, EPDM, silicon, polyimide, chloroprene, neoprene, butyl rubber, and SBR can also be used.

In particular, it is preferable to use a single-cell or open-cell flexible foam such as polyethylene, polyurethane, silicone, or neoprene as the foam member 28 in order to prevent clogging of the toner and improve durability. It is preferable to use a single-cell foam. Setting the cell density in the surface layer of the foam member 28 to 1 to 20 cells / mm is suitable for supplying the toner 7 to the surface of the toner carrier 32 while holding the toner 7 in the surface layer of the foam member 28. That is, the toner can be efficiently supplied to the surface of the toner carrier 32 without being affected by the change in the particle diameter or the fluidity of the toner 7. However, if the cell density is less than 1 cell / mm or 20
It is practically difficult to sufficiently hold the toner on the surface layer of the foamed member exceeding the number of pieces / mm, and the toner slips or falls off the surface layer of the foamed member due to the rotation of the supply member, and the Insufficient supply of toner occurs, resulting in uneven conveyance and insufficient conveyance amount in the toner layer on the surface of the toner carrier.

The cell density of the foamed member 28 is determined from the displacement curve and the enlarged image of the surface layer in a region where the surface layer of the foamed member is enlarged using a laser microscope (manufactured by Lasertec). Is determined by calculating the number of cells per unit length existing on an arbitrary straight line by separating into a cell forming region by foaming and an unfoamed solid region.

Further, the supply member 26 is connected to the toner carrier 32.
Is arranged so as to be rotatable with a contact pressure of 2 to 20 gf / mm, because a non-uniform layer of toner remaining as a consumption history on the surface of the toner carrier 32 after development is peeled off and a new toner layer is adhered. Because it is suitable for forming
The toner layer is adhered and formed by holding the toner, which is frictionally charged by being narrowly pressed on the surface of the toner carrier and the surface layer of the supply member, on the surface of the toner carrier. However, when the supply member is disposed at a contact pressure of less than 2 gf / mm with respect to the toner carrier, the non-uniform layer of the toner remaining after the development cannot be peeled off, and the consumption history of the toner in the subsequent development cycle is reduced. It has the disadvantage of appearing as an afterimage. When the contact pressure is set to 20 gf / mm or more, the driving torque of the developing device is increased, and the toner sandwiched between the supply member and the toner carrier is aggregated, thereby deteriorating the image quality. .

Therefore, by disposing a supply member formed of a foamed member having conductivity and a predetermined cell density at a predetermined contact pressure with respect to the toner carrier, a high-density solid continuous in the developing direction is provided. Even if the image is developed, a high-quality image with no afterimage can be obtained with good reproducibility over a long period of time without lowering the density at the rear end of the solid image. Further, by setting the compression set of the foam member 24 constituting the supply member 26 to 30% or less, more preferably 20% or less,
Variations in the contact pressure of the supply member 26 with respect to the toner carrier 32 can be prevented, and the supply and separation of the toner 7 to and from the toner carrier 32 can be performed stably.

For the supply member in which the compression set of the foam member 24 exceeds 30%, the developing device 31 provided with the supply member 26 that comes into contact with the toner carrier 32 or the charging auxiliary member 44.
When the supply member 26 is allowed to stand for a long time, the supply member 26 is permanently deformed at a contact portion with the toner carrier 32 or the charging auxiliary member 44. When the contact portion of the supply member 26 has been permanently deformed by a predetermined amount or more, immediately after the developing device 31 is driven, the permanent deformation portion of the supply member 26 is
, A required amount of contact pressure cannot be applied to the toner carrier 32, so that a toner peeling failure remaining as a consumption history on the surface of the toner carrier 32 after development and a defective supply of a new toner layer occur at the same time.
These appear as a decrease in the density of a solid image or an afterimage during image formation. However, the foam member 2 constituting the supply member 26
If the compression set of No. 4 is 30% or less, since the amount of permanent deformation of the supply member is small, the toner is sufficiently peeled and supplied to the toner carrier 32, and high-quality images without lowering the density of a solid image or remaining images are obtained. Images can be obtained.

By applying a developing bias voltage to at least two of the toner carrier 32, the supply member 26, and the regulating member 35, charges of opposite polarity generated by frictional charging between these members and the toner 7 are supplied to a power source or the like. The density fluctuation due to the accumulation of unnecessary charges can be prevented, and a stable development state can be maintained. However, in order to prevent the generation of the fixed layer due to the adhesion of the toner 7, it is preferable to apply the developing bias voltage to a member other than the insulating member.

The photosensitive layer 3 of the latent image carrier 1 can be made of an organic or inorganic photosensitive material.

The arrows in the figure indicate the direction of rotation of each member.
The peripheral speed ratio between the latent image carrier and the toner carrier is preferably in the range of 1: 1 to 1: 5, but the present invention is not limited to these figures and numerical values. Further, the developing device of the present invention is preferably used for pressure contact development, but may be used for a developing device requiring thin layer formation of toner in contact development or non-contact development.

The toner 7 may be a magnetic toner or a non-magnetic toner.
When the magnet 6 is formed by a magnet, the toner supply amount can be stabilized. The toner 7 may be a resin-based or wax-based toner, and may contain an external additive such as colloidal silica. The composition of the developer is not limited to one component. When a system toner is used, the volume average particle diameter is preferably in the range of 3 to 15 μm.

FIG. 2 is a schematic view of another toner carrier 22, in which a foam member 24 having foam cells of about several tens to 1,000 μm is formed around a shaft 23 made of metal or resin. Further, a flexible layer 25 having a thickness of about several tens to several hundreds μm is formed on the outer periphery thereof. By forming the toner carrier 22 with the foam member 24 and the thin flexible layer 25 having a small surface elasticity so that the rubber hardness (JIS A) is 40 degrees or less, the foam member constituting the supply member 26 is formed. And the frictional load between them can be reduced. Similarly, even at a low developing pressure of 5 gf / mm or less, the developing nip length can be set to 1 mm or more, and soft pressure contact development can be stably performed.

As the foam member 24, a polyurethane foam is used in the present embodiment, but other foams can be used similarly to the foam member 28 forming the supply member 26 described above. In particular, flexible foams such as polyethylene, polyurethane, silicone, and neoprene are suitable as the foamed material 24. Among them, polyurethane foams are excellent in moldability and have high hydrophilicity, so that flexible surfaces such as a conductive layer and a magnetic field generating layer are formed on the surface. Suitable for forming a functional layer.

The flexible layer 25 may be a single layer or a multilayer.
When a conductive flexible layer is used, high-resolution printing can be performed by the development electrode effect. When a ferromagnetic flexible layer is used, magnetic toner can be conveyed by magnetic force, and abrasion resistance is improved. The use of a flexible layer can protect the surface and improve the durability, and the use of a chargeable flexible layer allows the toner to be rapidly charged to a predetermined charge amount to improve the chargeability of the toner. It is possible to improve.

In this embodiment, the flexible layer 25 is formed of a conductive heat-shrinkable layer in which carbon black is dispersed in a main binder made of polyurethane. Similarly, as the main binder, a fluororesin, polyethylene, polyimide, It can be formed of polyester, polystyrene, polypropylene, polybutadiene, acrylic resin, PVA, silicone, polyamide, or the like. Further, as a conductive material, graphite, metal powder, metal complex salt, metal oxide, or the like can be used. Magnetite, ferrite, γ-hematite, iron, nickel, cobalt, iron-nickel alloy, iron-cobalt alloy, nickel-cobalt alloy, etc. can be used as the magnetic material, and graphite, disulfide Use molybdenum, boron nitride, etc. Can, as further charging material, metal complex, can be used quaternary ammonium salts.

FIG. 3 is a schematic view of a charging auxiliary member arranged to rub against the supply member 26 via the toner 7.
The charging auxiliary member is formed of a material located on the opposite side of the triboelectric charging polarity of the toner 7 from the triboelectric charging sequence.
And the supply member 2
The toner 7 held on the toner 6 is triboelectrically charged to a desired polarity in advance, thereby making it easier to form a toner layer on the toner carrier 32.

FIG. 3A shows a charging auxiliary member 45 in the form of a flexible blade made of a rubber plate, an elastomer plate, a resin thin plate or a metal thin plate provided on the supply member. (B) shows a rigid blade-shaped charging auxiliary member 46 made of a resin plate, a metal plate, or a ceramic plate disposed on the supply member. (C) shows a charging auxiliary member 47 in the form of a rubber elastic roller, an elastomer elastic roller, a resin rigid roller, a metal rigid roller, or a ceramic rigid roller, which is fixed or rotatably supported on the supply member. (D)
Shows an elastic blade-shaped charging auxiliary member 48 in which the tip of a rubber plate, an elastomer plate, a resin thin plate, or a metal thin plate is bent in an L-shape, and is disposed so as to be pressed against the supply member in the vicinity of the tip. The contact pressure of the charging auxiliary member with respect to the supply member 26 is 0.5 to 10 gf / m.
m is desirable.

The material used for the charge assisting member is a material in which at least the surface of the contact portion with the supply member 26 is located in the opposite polarity to the toner 7 in the triboelectric series, and for example, the triboelectric charge polarity of the toner 7 is positive. In the case of, a fluororesin, polyethylene, epoxy resin, urea resin, polyimide, polyester, polystyrene, polypropylene, polybutadiene, an organic material such as SBR, and a metal complex dye such as a Cr complex salt, a Zn complex salt, a Fe complex salt, and an Al complex salt are used alone. Alternatively, when the triboelectric charge polarity is negative, organic materials such as nylon, melamine resin, acrylic resin, PVA, polyurethane and silicone, quaternary ammonium salts and nigrosine dyes may be used alone or mixed. Can be used.

Further, Ti, Sn, Fe, Cu, Cr, N
metal materials such as i, Zn, Mg, Al, TiO ₂ , Sn
O ₂ , Fe ₂ O ₃ , Fe ₃ O ₄ , CuO, Cr ₂ O ₃ , Ni
Inorganic materials such as O, ZnO, MgO, and Al ₂ O ₃ can be used alone or in combination regardless of whether the toner 7 has a positive or negative triboelectric charge polarity. Of course, the organic material, the metal material, the inorganic material, and the like may be used in combination so as to be suitable for the triboelectric charging polarity of the toner 7.

The triboelectric series of materials used for the auxiliary charging member is obtained by using a surface potentiometer to determine the polarity of the surface potential generated when two types of materials selected arbitrarily are contact-charged in an electrically shielded space. It is determined by measuring and ranking the relationship between the positive electrode and the negative electrode of the material. When the toner 7 is used by being charged to the positive polarity, it is preferable that the charging auxiliary member be made of a material that is located farther away from the toner 7 than on the negative side. It is preferable to select a material for the charging assisting member that is located farther to the positive polarity side than the toner 7. Further, the charging auxiliary member may have conductivity, and may be disposed at the same potential as the supply member 26, or may be provided with a potential difference.

In FIG. 4, with respect to a horizontal line 51 passing through the center of the toner carrier 32, the supply member 26 is arranged such that a line 52 connecting the center of the toner carrier 32 and the center of the supply member 26 forms an angle α. The regulating member 35 is arranged below such that a line connecting the center of the toner carrier 32 and a contact portion of the regulating member 35 forms an angle β.

The supply member 26 is provided with the toner carrier 3 after development.
The supply member 26 mechanically peels off the non-uniform layer of the toner 7 remaining on the toner 2 while removing electricity, and frictionally charges the toner 7 again with new toner sent from the toner storage container. Supply. Supply member 2
6, the toner carrier 32
Above the wedge-shaped portion formed by the toner and the supply member 26, a vortex flow of toner is generated as shown by an arrow 54, and this vortex flow tends to become an unsteady flow due to the amount of toner on the toner supply member 26 and the like. . Therefore, it is desirable that the contact position between the regulating member 35 and the toner carrying member 32 is arranged so as to be hardly affected by the unsteady flow of the toner with respect to the supply member 26.

Further, the regulating member 35 reduces the thickness of the toner on the toner carrier 32 in a range of about one-hundredth to one-hundredth before and after passing through the regulating member 35. Due to the effect of the toner regulated by the regulating member 35, a vortex flow of the toner as shown by an arrow 55 also occurs near the leading end of the regulating member 35, but the positional relationship between the regulating member 35 and the supply member 26 is By setting the central angle of the body 32 to 45 ° to 90 °, the regulated toner can be recirculated onto the supply member 26, and a stable supply and regulated state can be maintained. Further, the above arrangement can reduce the mutual influence of the two vortex flows of the toner indicated by the arrows 54 and 55, and the toner thin layer can be stably formed by the configuration in consideration of the toner flow. Can be performed.

FIG. 5 shows the toner supply characteristics and the toner thin layer regulation characteristics using the angles α and β as parameters in the developing device as shown in FIG. This will be described below with reference to FIG. Note that the map of FIG. 5 shows that the outer diameter of the toner
Has an outer diameter of 12.5 mm, the toner carrier 32 and the supply member 2
This is an example in which the center-to-center distance with the number 6 is 16 mm.

For an angle α formed by a line 52 connecting the center of the toner carrier 32 and the center of the supply member 26 with respect to the horizontal line 51, in an area a where α ≦ 0 °, the angle between the toner carrier 32 and the supply member 26 A wedge-shaped toner pool is generated near the contact portion, and the toner supply amount is reduced every time the number of printed sheets is increased, and the density of a printed image is reduced. In the region c of α ≧ 45 °, a sufficient amount of toner cannot be held on the supply member 26, and the density of the printed image is reduced as the amount of toner on the supply member 26 decreases. In the region c of 0 ° ≦ α ≦ 45 °, the toner is held on the supply member 26 to supply a sufficient amount of toner, and the wedge-shaped toner pool is formed at the contact portion between the toner carrier 32 and the supply member 26. Does not occur.
Therefore, α is desirably about 0 ° to 45 °, and more desirably about 30 °.

Further, the toner carrier 3 is
In the region d where β ≦ 0 °, the angle β formed by the line connecting the horizontal line 51 passing through the center of 2 and the contact portion of the regulating member 35 is:
Since the toner pool exists near the tip of the regulating member 35, an excessive pressure is generated at the tip of the regulating member 35 depending on the amount of stored toner, and the toner is not conveyed.
Damage to members such as the toner carrier 32, or
Since a toner pool is present near the tip of the regulating member 35, a toner fixing layer is easily generated at the tip of the regulating member 35, and the toner fixing layer causes uneven toner layer thickness and a portion where no toner is present. Uneven density occurs in the image.

In the region f of β ≧ 105 °, the regulating member 35
The toner is not recirculated in the vicinity of the tip of the toner, and a toner pool is generated, and a toner fixed layer is easily generated at the tip of the regulating member 35, or an excessive pressure is generated at the tip of the regulating member 35. Toner thinning cannot be performed, and toner adhesion (ground fog) to non-image areas due to low-charge toner or reverse-polarity charge toner does not occur, or the toner charge amount decreases as the number of prints increases. The amount of developed toner increases.

In the region e of 0 ° ≦ β ≦ 105 °, toner accumulation is less likely to occur at the tip of the regulating member 35, and the toner regulated by the regulating member 35 is returned to the supply member 26 to achieve stable toner circulation. A thin toner layer can be formed. Therefore, β is desirably about 0 ° to 105 °,
More preferably, it is around 45 °.

Further, the toner carrier 32 and the supply member 26
Region g of α + β ≦ 45 ° with respect to the center angle α + β with respect to the rotation center of the toner carrier 32 from the contact position with the toner carrier 32 to the contact position between the toner carrier 32 and the regulating member 35.
In this case, due to the vortex flow of the toner generated by the supply member 26, the unevenness of the toner layer and the adhesion of the toner to the regulating member 35 occur, and the density unevenness increases each time printing is performed.

In the region h of α + β ≧ 90 °, although the toner layer can be thinned almost stably, it is difficult to recirculate the toner regulated by the regulating member 35 onto the supply member 26, and toner accumulation occurs. Therefore, in order to maintain a stable print image density, it is necessary to additionally arrange other members to stabilize the toner circulation.

In the region i of 45 ° ≦ α + β ≦ 90 °, the toner is stably supplied to the toner carrier 32 without the necessity of adding any other member, and the toner is stably supplied by the regulating member 35 to 1-2. The toner is thinned to about a layer, and the regulated toner is recirculated onto the supply member 26 to stably circulate the toner.
An image with less density unevenness can be continuously formed. Therefore, α + β is desirably about 45 ° to 90 °, and more desirably about 70 °.

When the above angle ranges are combined, in the area indicated by the hatched portion 61 in FIG. 5, the toner supply to the toner carrier is stably performed, and the toner layer on the toner carrier after the toner supply is completed is thinned. The regulation can be stably performed, and the toner circulation inside the developing device can be stably performed. Therefore,
High-resolution images can be formed with little density fluctuation over a long period of time.

Further, the cell density of the surface layer of the supply member 26 is d cells / mm, and the peripheral speed of the toner carrier 32 is V ₁ mm / mm.
sec, the peripheral speed V ₂ mm / sec of the supply member 26,
When the contact pressure is fgf / mm, the arrangement condition of the toner carrier 32 and the supply member 26 satisfies the relationship of 10 ≦ d * f * (V ₁ + V ₂ ) / V ₁ ≦ 200. As a result, the non-uniform layer of the toner 7 remaining as a consumption history on the surface of the toner carrier 32 after the development is mechanically peeled off while removing static electricity, and is evenly frictioned again with new toner sent from the toner storage container. By supplying the toner to the toner carrier 32 after charging, a uniform toner layer can be formed on the surface of the toner carrier. In particular, in order to efficiently form a layer of the toner having poor fluidity and triboelectricity remaining in the toner storage portion after the development is repeated many times on the surface of the toner carrier, the cell density d in the surface layer portion of the supply member is required. And the contact pressure f between the supply member and the toner carrier is important.

That is, the ability of the supply member rotating at the peripheral speed V ₂ to supply toner to the toner carrier rotating at the peripheral speed V ₁ is represented by d * (V ₁ + V ₂ ) / V ₁ . However, the ability to form a layer by holding a new toner on the surface of the toner carrier is further improved by multiplying the contact pressure f by d *
f * (V ₁ + V ₂ ) / V ₁ . The contact pressure f contributes to the efficiency of removing the toner remaining on the surface of the toner carrier and the efficiency of forming a toner layer on the toner carrier by frictionally charging the toner.

In order to continue to form a uniform toner layer on the surface of the toner carrier over a long period of time by using a toner having poor fluidity and triboelectricity, it is necessary to optimize the above-described toner peeling and layer forming efficiency. It is necessary to configure the developing device
From our research, d * f * (V ₁ + V ₂ ) / V ₁ <10
Under the conditions (1) and (2), the formation of the toner layer on the surface of the toner carrier is incomplete due to the deterioration of the toner, and the uneven toner layer remaining as the consumption history of the toner after development cannot be peeled off. It has been found that a drop in density and an afterimage occur at the rear end of the solid image during formation.

D * f * (V ₁ + V ₂ ) / V ₁ > 20
Under the condition of 0, the developing device causes an increase in the driving torque and a change in the rotational speed, so that the jitter is remarkably generated in the image, and the aggregation of the toner and the deterioration of the supply member also occur. Further, when the development was repeated, it was found that black spot-like background stains and image white spots were caused by the coarse aggregated powder. Therefore, by satisfying the relational expression 10 ≦ d * f * (V ₁ + V ₂ ) / V ₁ ≦ 200, even if a high-density solid image continuous in the developing direction is developed, It is possible to obtain a high-quality image with no afterimage over a long period of time with good reproducibility without lowering the density.

FIG. 6 is a schematic view of a developing device according to another embodiment of the present invention, in which a blade made of a non-magnetic or magnetic metal or resin is applied to a toner carrier 12 for carrying a toner 7. Or a cylindrical regulating member 15 is pressed by a pressing means 16 using an elastic body such as a spring or rubber,
The regulating member 15 is elastically deformed, the toner 7 is charged to a predetermined polarity at the contact portion of the toner carrier 12, and the toner layer is thinned to about one or two layers. Toner carrier 1
No. 2 has at least a surface formed of a foamed member having a rubber hardness (JIS A) of 40 degrees or less, and can be easily deformed when a rigid body is brought into contact therewith. Similarly, by forming the toner carrier 12 with a foam member having a hardness of 40 degrees or less (JIS A) or less, a developing nip length of 1 mm or more can be obtained even at a low developing pressure of 5 gf / mm or less. Development can be performed stably.

The toner carrier 12 is formed by forming a foam member 14 having foam cells of several tens to 1,000 μm on the outer periphery of a shaft 13 formed of metal or resin. The polyurethane foam is used for the foaming member 14 in this embodiment, but other foams can be used similarly to the foaming member 28 forming the supply member 26 described above. The supply member 17 has a cylindrical solid member 19 formed of metal, resin or hard rubber formed on the outer periphery of a shaft 18 formed of metal or resin so that the surface has a surface roughness of about several tens of μm. It was done.

FIG. 7 shows a method for measuring the resistance of the toner carrier used in the developing device of the present invention.
In a state where a load of 500 gf is applied to each of the shafts at both ends of 1 and the toner carrier 41 is pressed against the conductive plate 42,
A resistance meter 43 is connected between the shaft of the toner carrier 41 and the conductive plate 42 to measure the resistance. According to such a measuring method, it is possible to estimate the resistance at the nip between the toner carrier and the latent image carrier, so that a developing current of about several μA, which is a developing current in solid black printing, flows. Has 10 ⁹ Ω
A toner carrier having the following resistance is desirable. However, even in the case of a high-resistance or insulating toner carrier having a higher resistance, printing can be continued by adding a charge elimination mechanism for the toner carrier, so that the resistance is not limited to this.

Hereinafter, more detailed embodiments will be described.

Example 1 A developing device and an image forming device as shown in FIG. 1 were constructed using a toner carrier, a supply member and a regulating member as shown in (1) to (3) below. Using a 9 μm mono-component non-magnetic toner, a developing bias voltage was applied to the toner carrier, the supply member, and the regulating member to form an image.

Toner Carrier A conductive urethane rubber is formed around a stainless steel shaft, the outer peripheral surface thereof is polished, and then only the outer peripheral surface layer is subjected to a hardening treatment by heat or light to obtain a surface roughness Rz.
5 μm, rubber hardness (JIS A) 50 degrees, outer diameter 20
mm, a rubber thickness of 6 mm, and a toner carrier having a resistance of 10 ⁷ Ω according to the resistance measurement method of FIG. 7 were used.

Supply Member An open-cell polyurethane foam having a cell density d of 5 cells / mm (cell diameter of foam is about 200 μm on average) was formed around a stainless steel shaft, and the rubber hardness (JIS)
A) is 30 degrees, outer diameter is 12.5 mm, and foam thickness is 3.
Using a supply member having a length of 25 mm, the center distance between the toner carrier and the supply member was set to 16 mm and pressed against the toner carrier.

Restriction Member The tip of a stainless steel leaf spring material having a thickness of 0.1 mm is bent into an L shape, and the vicinity of the tip is 5 gf /
mm.

Using the developing device having such a configuration, a printing pattern including a gray scale image, a line image, a solid image, and a character image having a resolution of 300 DPI can be formed by 50.
When continuously formed over 00 sheets, a dot image and a line image of 300 DPI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed. Also, a clear character image without background fog was formed, and a solid image with a high density without an uneven density at an OD value of 1.4 or more could be formed stably. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion of the toner to the toner carrier, the supply member, or the regulating member was observed, and no damage to the toner was observed.

On the other hand, conductive urethane rubber is formed around a stainless steel shaft, and after polishing the outer peripheral surface, only the outer peripheral surface layer is subjected to a hardening treatment by heat or light so that the surface roughness becomes Rz. 5μm, rubber hardness (JIS
A) is a toner carrier having 70 degrees, an outer diameter of 20 mm, a rubber thickness of 6 mm, and a resistance of 10 ⁷ Ω. The cell density d of the foam material is 5 cells / mm (the foam cell diameter is about 200 μm on average).
m) Open cell polyurethane foam is formed around a stainless steel shaft and has a rubber hardness (JIS A) of 30.
A supply member having an outer diameter of 12.5 mm and a foam thickness of 3.25 mm is pressed into contact with a regulating member formed by bending the tip of a stainless steel leaf spring material having a thickness of 0.1 mm into an L shape. Using a developing device pressed at 5 gf / mm,
When an image was formed under the same conditions, a thin toner layer was stably formed on the toner carrier.

However, a soft pressed state between the latent image carrier and the toner carrier cannot be obtained, density unevenness occurs on the left and right sides of the image, and only an image having blurred images and many white spots in a solid image portion is formed. I couldn't do that. After the printing test, many scratches were generated on the surface of the latent image carrier and the toner carrier.

Further, conductive urethane rubber is formed around a stainless steel shaft, and after polishing the outer peripheral surface, only the outer peripheral surface layer is subjected to a hardening treatment by heat or light to have a surface roughness of 5 μm in Rz. , Rubber hardness (JIS A)
Is 50 degrees, outer diameter is 20 mm, rubber thickness is 6 mm, resistance is 1
0 ⁷ Omega toner carrying member used in here subjected to sandblasting an aluminum cylinder, the surface roughness in Rz 20 [mu]
m, a supply member having an outer diameter of 12.5 mm was pressed against the plate, and a regulating member having a chamfered front end of a stainless steel plate material having a thickness of 3 mm was pressed against the tip of the plate at 5 gf / mm under the same conditions. When the image was formed, the driving torque of the toner carrier and the supply member was extremely increased, the rotation speed was also varied, and the image jitter, which was a horizontal stripe-like sharp density unevenness, was visually observed. Only an image having a lot of white spots in a solid image portion or a fray can be formed. After the printing test, many scratches were generated on the surface of the toner carrier.

[Example 2] Under the same conditions as in Example 1, urethane rubber made conductive as a toner carrier was formed around a stainless steel shaft, and the outer peripheral surface was polished. Only by heat or light curing treatment, the surface roughness is 5 μm in Rz, rubber hardness (JIS
A) is 50 degrees, outer diameter is 20 mm, rubber thickness is 6 mm, FIG.
Using a toner carrier having a resistance of 10 ⁷ Ω according to the resistance measurement method, the cell density d of the foamed material was 5 cells /
mm (an average cell diameter of about 200 μm) is formed around a stainless steel shaft, and has a rubber hardness (JIS A) of 30 degrees and an outer diameter of 12.5 mm.
mm, and a supply member having a foam thickness of 3.25 mm, and the center-to-center distance between the toner carrier and the supply member is 16 mm.
mm and pressed against the toner carrier, and a regulating member made of a urethane rubber and a flexible plate material having a thickness of 1.5 mm and adhered and fixed to a metal plate was used as a regulating member. When the image is formed by pressing at 5 gf / mm, dot images and line images of 300 DPI are formed stably without thickening the image, and a high-resolution image excellent in area gradation is formed. Was completed.

Further, a clear character image without background fog was formed, and a solid image having a high density with an OD value of 1.4 or more without density unevenness could be formed stably. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion of the toner to the toner carrier, the supply member, or the regulating member was observed, and no damage to the toner was observed.

[Embodiment 3] Under the same conditions as in Embodiment 1, conductive silicon rubber was formed as a toner carrier around a stainless steel shaft, and the outer peripheral surface thereof was polished. To remove the plasticizer and silicone oligomer, the surface roughness is 9 μm in Rz, and the rubber hardness (J
IS A) 45 degrees, outer diameter 20 mm, rubber thickness 6 m
m, a toner carrier having a resistance of 10 ⁴ Ω according to the resistance measurement method shown in FIG.
Is formed around a stainless steel shaft with an open cell polyurethane foam of 5 cells / mm (foam cell diameter is about 200 μm on average), rubber hardness (JIS A) is 30 degrees, outer diameter is 12.5 mm, foam meat Using a supply member having a thickness of 3.25 mm, the center distance between the toner carrier and the supply member was set to 16 mm, and the toner carrier was pressed against the toner carrier. Further, a 1.5 mm thick urethane rubber was used as a regulating member. Using a regulating member in which a flexible plate material was adhered and fixed to a metal plate, the vicinity of this tip was pressed against the toner carrier at 5 gf / mm to form an image. As a result, a dot image and a line image of 300 DPI were formed. A high-resolution image excellent in area gradation was formed stably without thickening.

Further, a clear character image without background fogging was formed, and a high density solid image having an OD value of 1.4 or more without density unevenness was able to be stably formed. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion of the toner to the toner carrier, the supply member, or the regulating member was observed, and no damage to the toner was observed. Further, the surface of the toner carrier was worn by 10 to 20 μm, but no effect on the image was observed.

Embodiment 4 Under the same conditions as in Embodiment 1, urethane rubber which has been made conductive as a toner carrier is integrally formed around a stainless steel shaft, and a metal fine powder is formed on the outer periphery thereof as a main component. Conductive urethane paint with a thickness of about 2
Coating at 0 μm, surface roughness 5 μm in Rz, rubber hardness (JIS A) 50 degrees, outer diameter 20 mm, rubber thickness 6
mm, a toner carrier having a resistance of 10 ⁷ Ω according to the resistance measurement method shown in FIG.
Is formed around a stainless steel shaft with an open cell silicone foam of 5 cells / mm (foam cell diameter is about 200 μm on average), rubber hardness (JISA) is 28 degrees, and outer diameter is 12.
A supply member having a thickness of 5 mm and a foam thickness of 3.25 mm was used, and the center-to-center distance between the toner carrier and the supply member was set to 1
6 mm, pressed against the toner carrier, and a regulating member having a stainless steel leaf spring material having a thickness of 0.1 mm and the tip of which is bent into an L shape was used as a regulating member. When the image is formed by pressing at 5 gf / mm, dot images and line images of 300 DPI are formed stably without thickening the image, and a high-resolution image excellent in area gradation is formed. Was completed.

Further, a clear character image without background fog was formed, and a high density solid image having an OD value of 1.4 or more without density unevenness could be stably formed. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed.

Further, no fixation or fusion state of the toner on the toner carrier, the supply member or the regulating member was observed, and no damage of the toner was observed.

Embodiment 5 Under the same conditions as in Embodiment 1, urethane rubber which has been made conductive as a toner carrier is integrally formed around a stainless steel shaft, and a carbon as a conductive powder is A magnetic paint containing barium ferrite as a black and magnetic powder is dispersed to a thickness of about 50
μm, magnetized at a fine pitch with a magnetization reversal pitch of 40 μm, rubber hardness (JIS A) 50 degrees, outer diameter 20 m
m, a rubber thickness of 6 mm, and a toner carrier having a resistance of 10 ⁷ Ω according to the resistance measurement method shown in FIG. 7, and a cell density d of a foam material of 5 cells / mm (an average foam cell diameter of about A 200 μm open cell EPDM foam is formed around a stainless steel shaft, the rubber hardness (JIS A) is 33 degrees, the outer diameter is 12.2 mm, and the foam thickness is 3.1 mm.
Using a supply member, the center-to-center distance between the toner carrier and the supply member was set to 16 mm and pressed against the toner carrier,
Further, as a regulating member, a regulating member in which the tip of a leaf spring material made of stainless steel having a thickness of 0.1 mm is bent into an L shape is used, and the vicinity of the tip is pressed against the toner carrier at 5 gf / mm to form an image. As a result, a dot image and a line image of 300 DPI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed.

Further, a clear character image without background fog was formed, and a solid image having a high density with an OD value of 1.4 or more without density unevenness could be stably formed. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and background fog of the image could be continuously formed. Furthermore, no fixation or fusion of the toner to the toner carrier, the supply member, or the regulating member was observed, and no damage to the toner was observed. Furthermore, even when the supply member is rotated at a small peripheral speed ratio with respect to the toner carrier, sufficient toner supply can be continued, and even if the pressing force of the regulating member is reduced, the toner thin layer can be stably formed. Was able to continue.

Example 6 A developing device and an image forming device as shown in FIG. 2 were constructed using a toner carrier, a supply member and a regulating member as shown in (1) and (2), and the volume average particle diameter was An image was formed by applying a developing bias voltage to the toner carrier and the supply member using a 9 μm mono-component non-magnetic toner.

Toner Carrier A foam made of a single-cell conductive polyurethane foam having an average cell diameter of about 20 μm is formed around a stainless steel shaft, and a heat-shrinkable conductive urethane tube is used around the outer periphery of the shaft. A flexible layer having a thickness of about 100 μm is coated with heat and an adhesive, and has a rubber hardness (JIS A) of 35 degrees, an outer diameter of 20 mm, a foam thickness of 6 mm, and a resistance of 10 ⁶ Ω according to the resistance measurement method shown in FIG. The used toner carrier was used.

Supply Member An open-celled polyurethane foam having a cell density d of 5 cells / mm (average foam cell diameter about 200 μm on average) is formed around a stainless steel shaft, and the rubber hardness (JIS)
A) is 30 degrees, outer diameter is 12.5 mm, and foam thickness is 3.
Using a supply member having a length of 25 mm, the center distance between the toner carrier and the supply member was set to 16 mm and pressed against the toner carrier.

Restriction Member The tip of a stainless steel plate having a thickness of 3 mm was chamfered, and the tip was pressed against the toner carrier at 5 gf / mm.

By using the developing device having such a configuration, a printing pattern including a gray scale image, a line image, a solid image, and a character image having a resolution of 300 DPI can be formed by 50.
When continuously formed over 00 sheets, a dot image and a line image of 300 DPI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed. Also, a clear character image without background fog was formed, and a solid image with a high density without an uneven density at an OD value of 1.4 or more could be formed stably. Further, although the driving torque of the toner carrier and the like increased somewhat, no fluctuation in the rotational speed was observed, and an image with less jitter and background fog was continuously formed. Furthermore, no fixation or fusion of the toner to the toner carrier, the supply member, or the regulating member was observed, and no damage to the toner was observed.

On the other hand, the foam cell diameter was about 20 μm on average.
m is formed around a stainless steel shaft using a conductive foam of a single cell with a thickness of about 100 μm using a heat-shrinkable conductive urethane tube on the outer periphery.
m flexible layer is coated with heat and an adhesive. A toner carrier having a rubber hardness (JIS A) of 65 degrees, an outer diameter of 20 mm, a foam thickness of 6 mm, and a resistance of 10 ⁵ Ω is used. A cylinder made of sand is subjected to sand blasting, and a supply member having a surface roughness of 20 μm in Rz and an outer diameter of 12.5 mm is pressed against the cylinder, and the tip of a stainless steel leaf spring material having a thickness of 0.1 mm is L-shaped. When the image was formed under the same conditions using a developing device in which the front end portion was pressed against the toner carrier at 5 gf / mm, the driving torque of the toner carrier and the supply member was extremely increased. In addition, fluctuations in the rotational speed also occurred, and image jitter, which was a sharp density unevenness in the form of horizontal stripes, was visually observed, and only an image with blurred images and many white spots in a solid image portion could be formed. In addition, the regulating member vibrates, causing uneven conveyance of the toner on the toner carrying member, resulting in uneven image density.

Further, a single-cell conductive polyurethane foam having a foam cell diameter of about 20 μm on average is formed around a stainless steel shaft, and the outer periphery thereof is formed using a heat-shrinkable conductive urethane tube. A flexible layer of about 100 μm is covered with heat and an adhesive, and has a rubber hardness (JIS
A) 35 degrees, outer diameter 20 mm, foam thickness 6 m
m, and a toner carrier having a resistance of 10 ⁶ Ω, and the cell density d of the foam material is 5 cells / mm (the foam cell diameter is about 2
(00 μm) open-celled polyurethane foam is formed around a stainless steel shaft, and the rubber hardness (JIS A)
Is 30 degrees, outer diameter is 12.5mm, and foam thickness is 3.25
mm, using a developing device in which a regulating member in which the tip of a leaf spring material made of stainless steel and having a thickness of 0.1 mm is bent in an L shape is pressed at 5 gf / mm. When the image was formed under the conditions, initially,
A dot image and a line image of 300 DPI are formed, and O
A high-density solid image having a D value of 1.4 or more could be formed.

However, thinning of the toner layer on the toner carrier was not sufficient, and the background fog increased each time printing was repeated. Further, once the image forming apparatus is stopped, when the next image forming apparatus is started, the driving torque of the toner carrier increases, and the vibration of the developing apparatus occurs. It is considered that this occurred because the tip of the regulating member bit into the toner carrier, and when the regulating member was observed after the printing test, a slight fold was formed near the fixed end of the regulating member.

[Embodiment 7] Under the same conditions as in Embodiment 6, the toner carrier has an average foam cell diameter of about 20 μm.
Is formed around a stainless steel shaft, and is made of a heat-shrinkable conductive urethane tube on the outer periphery.
Is coated with heat and an adhesive, and the rubber hardness (J
IS A) 35 degrees, outer diameter 20 mm, foam thickness 6
mm, using a toner carrier having a resistance of 10 ⁶ Ω according to the resistance measurement method shown in FIG.
Is formed around a stainless steel shaft with an open cell polyurethane foam of 5 cells / mm (foam cell diameter is about 200 μm on average), rubber hardness (JIS A) is 30 degrees, outer diameter is 12.5 mm, foam meat Using a supply member having a thickness of 3.25 mm, a center-to-center distance between the toner carrier and the supply member is set to 16 mm to press the toner carrier, and a polyurethane resin is injection-molded as a regulating member. When a regulating member formed into a plate shape having a curved surface and having a thickness of 4 mm was pressed against the toner carrier at 5 gf / mm to form an image, a dot image and a line image of 300 DPI became thicker. Thus, a high-resolution image excellent in area gradation was formed stably without being formed.

Further, a clear character image without background fog was formed, and a solid image having a high density with an OD value of 1.4 or more without density unevenness was able to be formed stably. Further, although the driving torque of the toner carrier and the like increased somewhat, no fluctuation in the rotational speed was observed, and an image with less jitter and background fog was continuously formed. Furthermore, no fixation or fusion of the toner to the toner carrier, the supply member, or the regulating member was observed, and no damage to the toner was observed.

Example 8 Under the same conditions as in Example 6, the toner carrier had a solid surface layer on the surface,
A conductive silicon rubber foam having an open cell diameter of about 200 μm at the center is formed around a stainless steel shaft, and carbon black as a conductive powder and barium ferrite as a magnetic powder are formed on the outer periphery of the silicon rubber foam. Is applied at a thickness of about 50 μm, magnetized at a fine pitch with a magnetization reversal pitch of 40 μm, rubber hardness (JIS A) is 35 degrees, outer diameter is 20 mm, foam thickness is 6 mm, and the resistance shown in FIG. The resistance by the measuring method is 10 ³
And a supply member having a cell density d of 5 cells / mm (foam cell diameter of about 200 on average).
μm) open-cell polyurethane foam is formed around a stainless steel shaft and has a rubber hardness (JIS A) of 3
A supply member having 0 degree, an outer diameter of 12.2 mm, and a foam thickness of 3.1 mm was used. The center distance between the toner carrier and the supply member was set to 16 mm, and the pressure member was pressed against the toner carrier, and further regulated. Injection molding polyurethane resin as
When a regulating member formed into a plate having a thickness of 4 mm and having a curved surface at the tip was pressed against the toner carrier at 5 gf / mm to form an image, a dot image and a line image of 300 DPI were formed. A high-resolution image excellent in area gradation was formed stably without thickening.

Further, a clear character image without background fog was formed, and a solid image having a high density with an OD value of 1.4 or more without density unevenness could be formed stably. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion of the toner to the toner carrier, the supply member, or the regulating member was observed, and no damage to the toner was observed.

Furthermore, even when the supply member was rotated at a small peripheral speed ratio with respect to the toner carrier, sufficient toner supply could be continued.

Example 9 A developing device and an image forming device as shown in FIG. 1 were constructed by using a toner carrier, a supply member and a regulating member as shown in (1) to (5), and the volume average particle diameter was Using a 9 μm mono-component non-magnetic toner, a developing bias voltage is applied to the toner carrier, the supply member and the regulating member, and the peripheral speed of the toner carrier is V ₁ = 32 mm / sec.
c, Image formation was performed by setting the supply member to rotate at a peripheral speed V ₂ = 32 mm / sec.

Toner Carrier A conductive urethane rubber is formed around a stainless steel shaft, and after polishing the outer peripheral surface, only the outer peripheral surface layer is subjected to a hardening treatment with a coupling agent so that the surface roughness is Rz. A toner carrier having 5 μm, a rubber hardness (JIS A) of 53 degrees, an outer diameter of 20 mm, a rubber thickness of 6 mm, and a resistance of 10 ⁷ Ω according to the resistance measurement method of FIG. 7 was used.

Supply Member Two types of open-cell conductive EPDM foams having different cell densities d of the foaming members are formed around a stainless steel shaft, and have an outer diameter of 12.5 mm and a foam thickness of 3.25.
The contact member was pressed against the toner carrying member by setting the contact pressure f of the supplying member to the toner carrying member under the following conditions. Condition A: cell density d = 9 cells / mm, contact pressure f = 5 gf /
mm Condition B: cell density d = 0.5 cells / mm, contact pressure f = 1 g
f / mm Regulation member The tip of a stainless steel leaf spring material having a thickness of 0.1 mm is bent into an L-shape, and the vicinity of the tip is 5 gf /
mm.

By using the developing device having such a configuration, a printing pattern including a gray scale image, a line image, a solid image, and a character image having a resolution of 300 DPI can be printed.
It was continuously formed over 00 sheets. FIG. 9 shows the relationship between the rotation period of the toner carrier and the image density when a continuous solid black image is formed in the developing direction using the developing device and the image forming device created with the above-described configuration. Condition A is a representative example of the present invention, and condition B is a comparative example of the present invention.

When the developing device is constructed using the foaming member of the condition A, the solid black image has a high image density (OD ≧ 1.4) without depending on the rotation period of the toner carrier. No image defects such as a decrease in the density of a solid black image and an afterimage (ghost) were observed even after continuous printing of 5000 sheets. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion of the toner to the toner carrier, the supply member, or the regulating member was observed, and no damage to the toner was observed.

On the other hand, when the developing device is constituted by using the foaming member under the condition B, the solid black image has a high image density (OD ≧ 1.4) at the front end of the first rotation cycle of the toner carrier. However, at the rear end after the second rotation cycle of the toner carrier, the image density was reduced (OD ≦ 1.2), and at the same time, an afterimage occurred. Further, after the continuous printing of 5000 sheets, the image density of the rear end portion of the solid support roller after the second rotation cycle of the solid black image is greatly reduced, and the degree of the afterimage is worse than the initial state. Was.

In the condition B, the image density of the solid black image decreases at the rear end of the second and subsequent rotation periods as compared with the front end of the first rotation period of the toner carrier. The toner formed in the first rotation of the toner carrier rotation cycle develops a sufficient adhesion due to the image force due to several frictional charges with the regulating member and the toner carrier, so that a dense and relatively thick toner layer is formed. While the toner is easy to form, the toner after the second rotation cycle of the toner carrier depends on the toner supply ability of the supply member and the toner layer forming ability, and when the toner supply and the triboelectric charging are insufficient, the toner is loose. To form a relatively thin toner layer.

The above tendency is a phenomenon that becomes remarkable when the fluidity or triboelectricity of the toner is reduced.
The reason why the solid black image after the continuous printing of 5000 sheets causes a remarkable decrease in image density at the rear end portion after the second rotation cycle of the toner carrier is described above. However, when a supply member formed of a foamed member having a predetermined cell density as in the condition A is disposed so as to contact the toner carrier at a predetermined contact pressure, a layer is formed on the surface of the toner carrier. The toner in the first rotation cycle of the toner carrier is scraped off by the supply member and replaced with new toner, so that it is difficult to form a dense and thick layer.

Further, the toner after the second rotation cycle of the toner carrier is efficiently friction-charged with an appropriate contact pressure from the supply member and develops a sufficient adhesive force to the surface of the toner carrier. The toner layers in the first and second rotations of the body rotation cycle can be formed on the toner carrier in a uniform state. Therefore, when the developing device is configured using the foaming member of the condition A, a solid black image can be obtained in a uniform state with a high image density even after continuous printing of about 5,000 sheets without depending on the rotation period of the toner carrier. Can be

Embodiment 10 A developing device and an image forming apparatus as shown in FIG. 1 are constructed by using the toner carrier, the supply member, the regulating member and the charging auxiliary member as shown in (1) to (5) below. Using a one-component non-magnetic toner having a particle diameter of 9 μm, a developing bias voltage is applied to the toner carrier, the supply member, and the regulating member, the supply member and the charging auxiliary member are set to the same potential, and ₁ = 32 mm
/ Sec, and the supply member was set to rotate at a peripheral speed of V ₂ = 32 mm / sec to perform image formation.

Toner Carrier A conductive urethane rubber is formed around a stainless steel shaft, the outer peripheral surface thereof is polished, and then only the outer peripheral surface layer is subjected to a curing treatment with a cross-linking agent to have a surface roughness of 5% at Rz.
μm, rubber hardness (JIS A) 55 degrees, outer diameter 20m
m, a rubber thickness of 6 mm, and a toner carrier having a resistance of 10 ⁷ Ω according to the resistance measurement method of FIG. 7 were used.

Supply Member The cell density d of the foam member is different (0.5 to 32).
Pieces / mm) Seven kinds of open-celled conductive polyurethane foams are formed around a stainless steel shaft and have an outer diameter of 12.5 mm.
mm, and the contact pressure f of the supply member with respect to the toner carrying member is 1 to 3 using a supply member having a foam thickness of 3.25 mm.
The pressure was changed to a value within a range of 5 gf / mm to press the toner carrier.

Restriction Member The tip of a leaf spring material made of stainless steel having a thickness of 0.1 mm is bent in an L shape, and the vicinity of the tip is 5 gf /
mm.

Charging Aid Member The tip of a stainless steel leaf spring material having a thickness of 0.1 mm is bent into an L shape, and the vicinity of the tip is supplied to the supply member at 1 gf / mm.
Pressed with. It was confirmed that the stainless steel constituting the charging auxiliary member was positioned positively in the triboelectric series with respect to the triboelectric charging polarity of the toner used in this example, and the toner was easily negatively charged.

Using the developing device having such a configuration, a printing pattern including a gray scale image, a line image, a solid image, and a character image having a resolution of 300 DPI can be formed by 50.
It was continuously formed over 00 sheets. FIG. 9 shows that when a solid image continuous in the developing direction is formed in a developing device provided as parameters of the cell density d of the foaming member constituting the supply member and the contact pressure f of the supply member with respect to the toner carrier,
FIG. 7 is a diagram illustrating practical arrangement conditions that enable a solid image to be favorably developed without causing a decrease in density at the rear end of the solid image and without causing the developing device to change in rotational speed.

Area a indicates a range in which the cell density in the surface layer of the supply member is 1 to 20 cells / mm, and area d indicates a contact pressure of the supply member against the toner carrier of 2 to 20 gf.
/ Mm range. A sufficient image density (OD ≧ 1.3) at the rear end of the solid black image is obtained in the area g where the area a and the area d intersect. there were. Further, the supply member having a cell density of 2 to 12 cells / mm in the area g is contacted with a contact pressure of 4 to 15 gf /
mm, higher image density (OD)
.Gtoreq.1.4) was obtained, and no image sticking was observed.

In the area b or the area c, the density is reduced at the rear end of the solid image because the cell density of the surface layer is 1 cell / m 2.
m or more than 20 units / mm. In the developing device, the supply member cannot substantially supply the toner to the toner carrier, and the toner conveyance amount is insufficient. occured. Further, in the area e, the developing device under the condition that the contact pressure of the supply member with respect to the toner carrier is less than 2 gf / mm causes the density decrease at the rear end of the solid image. Even though a sufficient amount of toner has been supplied, the toner layer has not been formed uniformly on the toner carrier, resulting in uneven toner conveyance.

Further, the area f is excluded from the practical area in which the solid image can be favorably developed, in a developing apparatus in which the contact pressure of the supply member with respect to the toner carrier exceeds 20 gf / mm. In this case, the frictional resistance generated between the supply member and the toner carrier increases the driving torque of the developing device, exceeding the allowable load limit of the motor for driving the developing device, making the operation unstable and easily causing jitter in the image. .

Therefore, by configuring the developing device under the condition of disposing the supply member representing the area g, no background fogging occurs in the non-image area, and furthermore, the character developability, the line image developability, and the area gradation are improved. An excellent image was obtained with good reproducibility. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion state of the toner was observed on the toner carrier, the supply member, or the regulating member, and neither toner aggregation phenomenon nor abrasion or breakage of the supply member occurred.

[Embodiment 11] A developing device and an image forming apparatus as shown in FIG. 1 were constructed by using the toner carrier, the supply member, the regulating member, and the charging auxiliary member as shown in (1) to (5), and Using a one-component non-magnetic toner having a particle diameter of 9 μm, a developing bias voltage is applied to the toner carrier, the supply member, and the regulating member, the supply member and the charging auxiliary member are set to the same potential, and the toner carrier is rotated at a peripheral speed V _1. = 32mm /
In a _second , image formation was performed by setting the supply member to rotate at a peripheral speed V ₂ = 32 mm / sec.

Toner Carrier A conductive urethane rubber is formed around a stainless steel shaft, and the outer peripheral surface thereof is polished. Then, only the outer peripheral surface layer is subjected to a curing treatment with a cross-linking agent to have a surface roughness of Rz of 5%.
μm, rubber hardness (JIS A) 55 degrees, outer diameter 20m
m, a rubber thickness of 6 mm, and a toner carrier having a resistance of 10 ⁷ Ω according to the resistance measurement method of FIG. 7 were used.

Supply Member Four types of open-cell conductive polyurethane foams having different compression set (cell density d = 2 to 12 cells / mm) are formed around a stainless steel shaft, and have an outer diameter of 12.5 m.
m, using a supply member having a foam thickness of 3.25 mm, and setting the contact pressure f of the supply member to the toner carrier to be 2 to 1
The pressure was changed to a value within a range of 5 gf / mm to press the toner carrier.

Restriction Member The tip of a stainless steel leaf spring material having a thickness of 0.1 mm is bent into an L-shape, and the vicinity of the tip is 5 gf /
mm.

Charging Aid Member A tip of a stainless steel leaf spring material having a thickness of 0.1 mm is bent into an L shape, and the vicinity of the tip is applied to a supply member at 1 gf / mm.
Pressed with. It was confirmed that the stainless steel constituting the charging auxiliary member was positioned positively in the triboelectric series with respect to the triboelectric charging polarity of the toner used in this example, and the toner was easily negatively charged.

Table 1 shows the results of continuously forming a print pattern including a grayscale image, a line image, a solid image, and a character image having a resolution of 300 DPI using the developing device having the above configuration. The presence or absence of an image defect that occurred after being allowed to stand for 7 days in a high humidity (35 ° C., 65% RH) environment was evaluated as ××. As a judgment method, five continuous solid images were continuously printed in the developing direction, and one in which a good solid image was obtained was evaluated as “good”. Those that disappeared in continuous printing of sheets were rated as △, and those in which the horizontal streak did not disappear in continuous printing of several sheets were rated as x.

[0121]

[Table 1]

Under the above conditions, no ground fogging occurred in the non-image area, and an image having excellent character developability, line image developability and area gradation was obtained with good reproducibility. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion state of the toner was observed on the toner carrier, the supply member, or the regulating member, and neither toner aggregation phenomenon nor abrasion or breakage of the supply member occurred.

[Embodiment 12] A developing device and an image forming apparatus as shown in FIG. 1 are constructed by using the same toner carrier, supply member and regulating member as in the embodiment 1, and the angle shown in FIG. Images were formed using a one-component non-magnetic toner having a volume average particle diameter of 9 μm, arranged so that α = 30 ° and β = 45 °.

By using the developing device having such a configuration, a printing pattern including a grayscale image, a line image, a solid image, and a character image having a resolution of 300 DPI can be formed by 50.
When continuously formed over 00 sheets, a dot image and a line image of 300 DPI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed. Also, a clear character image without background fog was formed, and a solid image with a high density without an uneven density at an OD value of 1.4 or more could be formed stably. Furthermore, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotational speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed.

Furthermore, no fixation or fusion of the toner to the toner carrier, the supply member, and the regulating member was observed, and no damage to the toner was observed. However, it was confirmed that normal image formation was performed by applying the developing bias voltage to at least two of the toner carrier, the supply member, and the regulating member. However, when the voltage was applied only to the supply member or when the voltage was applied only to the regulating member, the toner conveyance amount fluctuated, and only an image having large density unevenness was obtained.

On the other hand, the angles α and β shown in FIG.
Using a developing device arranged so that α = 30 ° and β = 120 °, 5,000 print patterns including a grayscale image, a line image, a solid image, and a character image with a resolution of 300 DPI were continuously formed. However, initially, thinning of the toner is performed, and 30
A dot image and a line image of 0 DPI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed. However, after printing several tens of sheets, the toner conveyance amount on the toner carrier became unstable, and uneven density and background fog occurred in printing. In addition, the density unevenness increases each time the number of printed sheets is increased, and after printing 1,000 sheets, white vertical strips are occasionally generated on printed matter. 5
After printing 000 sheets, a toner layer which could not be easily peeled off adhered to the tip of the regulating member. However, the developing bias voltage was applied to the toner carrier, the supply member, and the regulating member.

[Embodiment 13] A developing device and an image forming apparatus as shown in FIG. 1 are constructed by using the same toner carrier, supply member and regulating member as in the embodiment 6, and the angle shown in FIG. Images were formed using a one-component non-magnetic toner having a volume average particle diameter of 9 μm, arranged so that α = 30 ° and β = 45 °.

Using the developing device having such a configuration, a print pattern including a grayscale image, a line image, a solid image, and a character image having a resolution of 300 DPI can be printed in 50 prints.
When continuously formed over 00 sheets, a dot image and a line image of 300 DPI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed. Also, a clear character image without background fog was formed, and a solid image with a high density without an uneven density at an OD value of 1.4 or more could be formed stably. Furthermore, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotational speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed.

Further, no fixation or fusion state of the toner on the toner carrier, the supply member, and the regulating member was observed, and no damage to the toner was observed. However, it was confirmed that normal image formation was performed by applying the developing bias voltage to at least two of the toner carrier, the supply member, and the regulating member. However, when the voltage was applied only to the supply member or when the voltage was applied only to the regulating member, the toner conveyance amount fluctuated, and only an image having large density unevenness was obtained.

On the other hand, the angles α and β shown in FIG.
Using a developing device arranged so that α = 45 ° and β = 0 °, 50 print patterns including a grayscale image, a line image, a solid image, and a character image with a resolution of 300 DPI were continuously formed. However, in the initial few sheets, the toner is thinned, and the 300D
The dot image and line image of PI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed. However, after printing several sheets, the amount of toner transported on the toner carrier increased, and uneven transport occurred, resulting in uneven density and background fogging in printing. However, the developing bias voltage was applied to the toner carrier, the supply member, and the regulating member.

Example 14 A developing device and an image forming device as shown in FIG. 1 were constructed by using a toner carrier, a supply member, and a regulating member as shown in (1) to (4) below. Using a 9 μm mono-component non-magnetic toner, a developing bias voltage is applied to the toner carrier, the supply member and the regulating member, and the peripheral speed of the toner carrier is V ₁ = 32 mm /
In a _second , image formation was performed by setting the supply member to rotate at a peripheral speed V ₂ = 32 mm / sec.

Toner Carrier A conductive urethane rubber is formed around a stainless steel shaft, and after polishing the outer peripheral surface, only the outer peripheral surface layer is subjected to a hardening treatment by heat or light, and the surface roughness is reduced to Rz.
5 μm, rubber hardness (JIS A) 50 degrees, outer diameter 20
mm, a rubber thickness of 6 mm, and a toner carrier having a resistance of 10 ⁷ Ω according to the resistance measurement method of FIG. 7 were used.

Supply member The cell density d of the foam member is different (0.5 to 32).
Pieces / mm) Seven kinds of open-celled conductive polyurethane foams are formed around a stainless steel shaft and have an outer diameter of 12.5 mm.
mm, and the contact pressure f of the supply member with respect to the toner carrying member is 1 to 3 using a supply member having a foam thickness of 3.25 mm.
The pressure was changed to a value within a range of 5 gf / mm to press the toner carrier.

Restriction Member The tip of a stainless steel leaf spring material having a thickness of 0.1 mm is bent into an L-shape, and the vicinity of the tip is attached to the toner carrier at 5 gf / cm.
mm.

Using the developing device having the above configuration, a resolution of 3
A printing pattern including a gray scale image, a line image, a solid image, and a character image of 00 DPI is 5000
It was formed continuously over the sheets. FIG. 10 shows the relationship between the contact pressure of the supply member made of foamed members having different cell densities in the surface layer portion on the toner carrier and the output image from the developing device. (A) is a diagram showing a phenomenon of a decrease in density at the rear end of the solid black image, and shows a relationship between the contact pressure f of the supply member and the image density (OD) at the rear end of the solid black image. I have. FIG. 4B is a diagram illustrating the degree of an afterimage in which the consumption history of the toner on the toner carrier appears in correspondence with the rotation cycle of the toner carrier, and illustrates the contact pressure f of the supply member and the toner pressure on the toner carrier. The relationship is shown as a difference in the density (OD) of the solid black image corresponding to the toner consuming portion and the non-consuming portion. The difference between the toner consuming portion and the non-consumed portion on the toner carrier is that when a solid image is developed in the next rotation period of the toner carrier, a high image density is obtained in an area corresponding to the toner non-consuming portion, In the area corresponding to the toner consuming portion, when the toner agent is not sufficiently supplied, the image density is reduced, and this difference appears as a difference in image density, that is, an afterimage. Here, as a method of representing the degree of the afterimage, the result of calculating the density difference of the solid black image appearing in the next rotation cycle of the developing roller corresponding to the toner consuming portion and the non-consuming portion is shown.

Table 2 is a table summarizing the results obtained in FIG. As the evaluation criterion, the condition shown by “○” is a condition in which the image density of the solid black image is 1.3 or more and the image density difference representing the afterimage satisfies less than 0.2.
The symbol “△” indicates that the image density of the solid black image is 1.3 or more and the image density difference representing the afterimage is 0.2 to 0.3, or the image density of the solid black image is 1.2 to 1 0.3 and the image density difference representing the afterimage is less than 0.2, or the image density of the solid black image is 1.2 to 1.3 and the image density difference representing the afterimage is 0.2
This is a condition that satisfies ０．３0.3. What is indicated by "x" is
The condition is that the image density of the solid black image is less than 1.2 or the image density difference representing the afterimage is less than 0.3. The condition indicated by "-" indicates that the image forming apparatus used in this embodiment could not form an image because the driving load of the developing apparatus was large.

In the conditions shown by “O” in Table 2,
A dot image and a line image of 300 DPI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed. In addition, a clear character image having no background fog was formed, and a solid image having a high density and an OD value of 1.3 or more without density unevenness was able to be formed stably. Under the above conditions, no background fogging occurred in the non-image area, and an image excellent in character developability, line image developability, and area gradation was obtained with good reproducibility. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion state of the toner was observed on the toner carrier, the supply member, or the regulating member, and neither toner aggregation phenomenon nor abrasion or breakage of the supply member occurred.

[0138]

[Table 2]

[Embodiment 15] Under the same conditions as those in Embodiment 14, the toner carrier was moved at a peripheral speed V ₁ = 32 mm / sec.
c, Image formation was performed by setting the supply member to rotate at a peripheral speed V ₂ = 6.4 mm / sec. Table 3 summarizes the results obtained under the above conditions in a list. The evaluation criteria for the output image are the same as in the fourteenth embodiment.

In Table 3, under the conditions indicated by “O”,
A dot image and a line image of 300 DPI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed. In addition, a clear character image having no background fog was formed, and a solid image having a high density and an OD value of 1.3 or more without density unevenness was able to be formed stably. Under the above conditions, no background fogging occurred in the non-image area, and an image excellent in character developability, line image developability, and area gradation was obtained with good reproducibility. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion state of the toner was observed on the toner carrier, the supply member, or the regulating member, and neither toner aggregation phenomenon nor abrasion or breakage of the supply member occurred.

[0141]

[Table 3]

[Embodiment 16] Under the same conditions as in Embodiment 14, the toner carrier was moved at a peripheral speed V ₁ = 32 mm / sec.
c, Image formation was performed by setting the supply member to rotate at a peripheral speed V ₂ = 16 mm / sec. Table 4 summarizes the results obtained under the above conditions in a list. The evaluation criteria for the output image are the same as in the fourteenth embodiment.

In Table 4, under the conditions indicated by “O”,
A dot image and a line image of 300 DPI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed. In addition, a clear character image having no background fog was formed, and a solid image having a high density and an OD value of 1.3 or more without density unevenness was able to be formed stably. Under the above conditions, no background fogging occurred in the non-image area, and an image excellent in character developability, line image developability, and area gradation was obtained with good reproducibility. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion state of the toner was observed on the toner carrier, the supply member, or the regulating member, and neither toner aggregation phenomenon nor abrasion or breakage of the supply member occurred.

[0144]

[Table 4]

[Embodiment 17] Under the same conditions as those in Embodiment 14, the toner carrier was moved at a peripheral speed V ₁ = 32 mm / sec.
c, Image formation was performed by setting the supply member to rotate at a peripheral speed V ₂ = 64 mm / sec. Table 5 summarizes the results obtained under the above conditions in a list. The evaluation criteria for the output image are the same as in the fourteenth embodiment.

[0146]

[Table 5]

In Table 5, under the conditions indicated by “O”,
A dot image and a line image of 300 DPI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed. In addition, a clear character image having no background fog was formed, and a solid image having a high density and an OD value of 1.3 or more without density unevenness was able to be formed stably. Under the above conditions, no background fogging occurred in the non-image area, and an image excellent in character developability, line image developability, and area gradation was obtained with good reproducibility. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion state of the toner was observed on the toner carrier, the supply member, or the regulating member, and neither toner aggregation phenomenon nor abrasion or breakage of the supply member occurred.

[Embodiment 18] Under the same conditions as those in Embodiment 14, the toner carrier was moved at a peripheral speed V ₁ = 32 mm / sec.
c, Image formation was performed by setting the supply member to rotate at a peripheral speed V ₂ = 128 mm / sec. Table 6 summarizes the results obtained under the above conditions in a list. The evaluation criteria for the output image are the same as in the fourteenth embodiment.

[0149]

[Table 6]

In Table 6, under the conditions indicated by “O”,
A dot image and a line image of 300 DPI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed. In addition, a clear character image having no background fog was formed, and a solid image having a high density and an OD value of 1.3 or more without density unevenness was able to be formed stably. Under the above conditions, no background fogging occurred in the non-image area, and an image excellent in character developability, line image developability, and area gradation was obtained with good reproducibility. Further, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotation speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion state of the toner was observed on the toner carrier, the supply member, or the regulating member, and neither toner aggregation phenomenon nor abrasion or breakage of the supply member occurred.

[Embodiment 19] A developing device and an image forming apparatus as shown in FIG. 6 were constructed using a toner carrier, a supply member, and a regulating member as shown in (1) to (5) below. Using a 9 μm mono-component non-magnetic toner, a developing bias voltage was applied to the toner carrier, the supply member, and the regulating member to form an image.

Toner Carrier A single-cell, electrically conductive, flexible polyurethane foam having an average foam cell diameter of about 20 μm is formed around a stainless steel shaft, and has a rubber hardness (JIS A) of 30 degrees and an outer diameter of 20 mm.
mm, the foam thickness was 6 mm, and the toner carrier having a resistance of 10 ⁶ Ω according to the resistance measurement method shown in FIG. 7 was used.

Supply Member A supply member having a surface roughness Rz of 20 μm and an outer diameter of 12.5 mm is formed by sandblasting an aluminum cylinder, and the center distance between the toner carrier and the supply member is set at 1 mm.
It was set to 6 mm and pressed against the toner carrier.

Restriction member The tip of a stainless steel plate having a thickness of 3 mm was chamfered, and the tip was pressed against the toner carrier at 5 gf / mm.

By using the developing device having such a configuration, a printing pattern including a gray scale image, a line image, a solid image, and a character image having a resolution of 300 DPI can be formed by 50.
When continuously formed over 00 sheets, a dot image and a line image of 300 DPI were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed. Also, a clear character image without background fog was formed, and a solid image with a high density without an uneven density at an OD value of 1.4 or more could be formed stably. Furthermore, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotational speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion of the toner to the toner carrier, the supply member, or the regulating member was observed, and no damage to the toner was observed.

On the other hand, the foam cell diameter was about 20 μm on average.
m foamed around a stainless steel shaft, and a rubber hardness (JIS
A) is 60 degrees, outer diameter is 20 mm, foam thickness is 6 mm,
Using a toner carrier having a resistance of 10 ⁶ Ω, an aluminum cylinder was subjected to sandblasting, and the surface roughness was 20 Rz.
Using a developing device in which a supply member having an outer diameter of 12.5 mm and a regulating member having a chamfered tip of a stainless steel plate having a thickness of 3 mm was pressed at 5 gf / mm under the same conditions. When the image was formed, the driving torque of the toner carrier and the supply member was extremely increased, the rotation speed was also varied, and the image jitter, which was a horizontal stripe-like sharp density unevenness, was visually observed. Only an image having a lot of white spots in a solid image portion or a fray can be formed.

A single-cell, electrically conductive polyurethane foam having an average cell diameter of about 20 μm is formed around a stainless steel shaft, and has a rubber hardness (JIS A) of 3
0 degree, outer diameter 20 mm, foam thickness 6 mm, resistance 1
Using a toner carrier of 0 ⁶ Ω, an open-celled polyurethane foam having a cell density d of 5 cells / mm (foam cell diameter on average about 200 μm) is formed around a stainless steel shaft here, A supply member having a rubber hardness (JIS A) of 30 degrees, an outer diameter of 12.5 mm, and a foam thickness of 3.25 mm is pressed into contact with a supply member having a thickness of 0.1 m made of stainless steel.
An image was formed under the same conditions using a developing device in which a regulating member having a leaf spring material having an L-shaped end bent in an L-shape was pressed at 5 gf / mm under the same conditions. The formation was not sufficient, and the background fog increased each time printing was repeated. At the time before the end of the printing test, foreign matters considered to be fragments of the foamed member were sometimes observed on the image.

Further, once the image forming apparatus is stopped,
At the next start of the image forming apparatus, the driving torque of the toner carrier increased, and vibration of the developing apparatus occurred. This is considered to have occurred because the tip of the regulating member bit into the toner carrier, and when the regulating member was observed after the printing test,
There was a slight fold near the fixed end of the regulating member.

[Embodiment 20] Under the same conditions as in Embodiment 19, the foamed cell diameter of the toner carrier was about 20 on average.
A conductive polyurethane foam of a single-micron foam was formed around a stainless steel shaft, and the rubber hardness (JI
S A) 30 degrees, outer diameter 20 mm, foam thickness 6 m
m, an acrylic resin in which conductive carbon black is dispersed is injection-molded around a stainless steel shaft as a supply member using a toner carrier having a resistance of 10 ⁶ Ω according to the resistance measurement method shown in FIG. Using a supply member having an Rz of 15 μm and an outer diameter of 12.5 mm, the center distance between the toner carrier and the supply member is set to 16 mm and the toner carrier is pressed against the toner carrier. A dispersion member was injection-molded, and a regulating member formed into a 4 mm-thick plate having a curved surface at the tip was pressed against the toner carrier at 5 gf / mm to form an image. , 300 DPI dot image and line image were formed stably without thickening the image, and a high-resolution image excellent in area gradation was able to be formed.

Also, a clear character image without background fog was formed, and a solid image having a high density with an OD value of 1.4 or more without density unevenness could be formed stably. Furthermore, no increase in the driving torque of the toner carrier or the like and no fluctuation in the rotational speed were observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion of the toner to the toner carrier, the supply member, or the regulating member was observed, and no damage to the toner was observed.

[Example 21] Under the same conditions as in Example 19, the foamed cell diameter of the toner carrier was about 20 on average.
A conductive polyurethane foam of a single-micron foam was formed around a stainless steel shaft, and the rubber hardness (JI
S A) 30 degrees, outer diameter 20 mm, foam thickness 6 m
m, using a toner carrier having a resistance of 10 ⁶ Ω according to the resistance measurement method shown in FIG. 4, applying a magnetic paint in a thickness of about 100 μm to the outer periphery of an aluminum cylinder as a supply member,
micro-magnetization with a magnetization reversal pitch of m
Using a supply member having a magnetic attraction force of 16 mm, the center distance between the toner carrier and the supply member is set to 16 mm to contact the toner carrier, and a polyurethane resin is injection-molded as a regulating member. When a regulating member formed into a plate shape having a curved surface and a thickness of 4 mm was pressed against the toner carrier at 5 gf / mm to form an image, a dot image and a line image of 300 DPI thickened. Thus, a high-resolution image excellent in area gradation was formed stably without being formed.

Further, a clear character image without background fog was formed, and a high density solid image having an OD value of 1.4 or more without density unevenness could be stably formed. Further, the driving torque of the toner carrier and the like was reduced as compared with the case of Example 1 or Example 2, no fluctuation in the rotation speed was observed, and an image with less jitter and ground fogging of the image could be continuously formed. Furthermore, no fixation or fusion of the toner to the toner carrier, the supply member, or the regulating member was observed, and no damage to the toner was observed.

Although the embodiments have been described above, the present invention can be applied not only to the above-described embodiments but also to a wide range of developing apparatuses such as electrophotography. It is valid.

[0164]

As described above, according to the present invention, a toner carrier having a hardness higher than that of a supply member and a toner carrier which is relatively moved to supply the toner to the toner carrier are provided. Since the developing device is composed of the supply member that is pressed and the regulating member that is slidably contacted with the toner carrier so as to make the toner supplied on the toner carrier thinner, a soft elastic member is used for the soft device. Pressure contact development can be performed stably, and an image with high resolution and little density fluctuation can be formed. Further, the amount of toner transported on the toner carrier is kept constant irrespective of the remaining amount of toner and the print history, so that an image with less density unevenness and less print jitter can be formed. Further, the main parts of the developing device are constituted by a simple-shaped roller and a plate-shaped member, and it is possible to provide a developing device which is small, inexpensive, and excellent in durability.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a developing device showing one embodiment of the present invention.

FIG. 2 is a schematic view of a developing device showing another embodiment of the present invention.

FIG. 3 is a schematic view showing the arrangement of a charging auxiliary member according to one embodiment of the present invention.

FIG. 4 is a schematic view of a developing device showing still another embodiment of the present invention.

FIG. 5 is a view showing a toner supply characteristic and a toner thin layer regulation characteristic in the developing device of the present invention.

FIG. 6 is a schematic view of a developing device showing still another embodiment of the present invention.

FIG. 7 is a diagram showing a method for measuring the resistance of a toner carrier used in the developing device of the present invention.

FIG. 8 shows the relationship between the cell density of the foaming member constituting the supply member of the developing device, the contact pressure of the supply member with respect to the toner carrier, and the practical range in which a solid image can be favorably developed. FIG.

FIG. 9 is a diagram illustrating a relationship between a rotation period of a toner carrier and an image density of a developing device according to an embodiment of the present invention.

FIG. 10 is a diagram showing a relationship between a contact pressure of a supply member with respect to a toner carrier and an output image characteristic used in a developing device according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 latent image carrier 7 toner 11 21 31 developing device 12 22 32 41 toner carrier 14 24 28 foaming member 15 35 regulating member 17 26 supply member 19 34 solid member 45 46 47 48 charge assisting member

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Yoshihiro Nakajima 3-5-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation (72) Inventor Takehiko Okamura 3-5-2-5 Yamato, Suwa-shi, Nagano Seikoー Epson Corporation

Claims (1)

[Claims] 1. A toner carrier that is disposed opposite to the latent image carrier and that has a hardness greater than at least a supply member so as to visualize the latent image formed on the latent image carrier. A supply member that moves and presses against the toner carrier so as to supply the toner to the toner carrier and a regulation that slides on the toner carrier to reduce the thickness of the toner supplied on the toner carrier; A contact position between the toner carrier and the supply member is disposed below a rotation center of the toner carrier, and a contact position between the toner carrier and the regulating member is The rotation center of the toner carrier, which is disposed above the rotation center of the toner carrier and extends from a contact position between the toner carrier and the supply member to a contact position between the toner carrier and the regulating member. Against The central angle, developing apparatus is characterized in that a 45 ° or more 90 ° or less.